Device for positioning colorimeter cells



Dec. 18, 1945. D. s. STEVENS 2,391,076

DEVICE FOR POSITiONING'COLORIMETER CELLS Filed March 4, 1942 I W 25. as

In venfol Patented Dec. 18, 1945 UNlTED STATES PATENT? OFFICE 2,391,016DEVICE non POSITIONING ooLoRIMETEIt onus Daniel S. Stevens. Chicago,Ill. Application March 4, 1942, Serial No. 433,310

' This invention relates to a device for ing colorimeter cells.

One of the objects of this invention is to provide a simple means forproperly positioning the colorimeter cell in the light beam of aphotoelectric colorimeter.

Another object is to provide a means of securing the cell in place, oncethe proper position has been obtained.

A further object is to provide simple means for release of the cellafter use. A, still further object is to provide means for ejecting theused cell into a suitable receptacle against future disposition.

One form of the device of this invention is illustrated by the attachedfigures, of which:

Figure 1 illustrates the device in front elevation showing the means forpositioning and securing the cell.

Figure 2 is a plan view along line 22 of Figure 1.

Like numerals designate like parts throughout the several drawings.

The device consists of a holder member designated generally as l. Themember I is pivoted at 2 to admit of circular motion. A handle 3 isgrasped by the hand when it is desired to move the holder member aboutpivot 2. A stop post 4 is so positioned that it restricts the motion ofI in a counter-clockwise direction. Arresting post 4 is provided with anadjustable screw 5, which may be screwed in or out, thus providingadjustable means for bringing holder member I into proper position whenhandle 3 is rotated in a counter-clockwise direction.

Holder member I is provided with an opening forming two sides of asquare for receiving the colorimeter cell and bringing it into properalignment. The side 6 of this square is given a sharp edge throughbeveling. Side 1 of the square opening need not be beveled.

A securing member 9 consists of a metal casting having substantialweight. An arm I extending from 9 co-operates with a stud ll, said studacting as a pivot about which in may be turned. This securing member 9serves to hold the colorimeter cell in place by exerting a side pressureon the cell. The edge of the securing member which contacts thecolorimeter cell is also beveled, as indicated by [2. Member 9 is sosuspended from stud II that the beveled edge l2 occupies the samehorizontal plane as the beveled edge 6 of the holder member I.

If the beveled contact edges 6 and I2 were not in the same horizontalplane there would be a force tending to turn the colorimeter cell.Should position- 3 Claims. (01-. 88J-14) this occur the light paththrough the cell would be increased and an error in the reading 01 theinstrument would occur. The beveled construction allows precise locationof the holding force applied to the side of the cell.

A removable receptacle l3 provided in shelf I4 is so positioned thatwhen securing member 9 is moved upward by turnin on stud Hand handl 3 isrotated in a clockwise direction, the cell th n in the device is ejectedthereirom and drops into receptacle l3.

The many advantages of this device. particularly when used withcolorimetric cells cover d by my U. S. Patent #2258973. become obviouson a description of its operation with a suitable ph toelectriccolorimeter. 1

The light. source of such a colorimeter is a. small incandescent bulb I5mounted on a movable platform [6. This bulb can be operated irom astorage battery.

The movable platform slides on posts I! and H by turning screw wheel I8-. ".L'hisv screw wheel is mounted in threaded hub [9. Pressure fromsprings 20 and 20' gives a smooth motion to the movable platform 16.

Light from the bulb passes through conical opening 2! to reach thecolorimeter cell 22. A small hole in the tip of hollow cone 23 allowslight to enter and illuminate photocell 24. This photocell is connectedto a galvanometer by leads 25 and 25'. Motion of the galvanometer catedby hairline 26 and a scale 21.

In using such an instrument, it is necessary to check frequently thezero position of the galvanometer, by cutting off the electric currentthrough the galvanometer.

This is readily accomplished in the device of this invention byrotatingthe holding member I in a clockwise manner. When this is done,solid portion 28 of the holding member moves under the tip of the hollowcone, thus intercepting the light beam to the hotocell. Under theseconditions the galvanometer hairline should return to zero, or thenecessary adjustment can be made.

To make a colorimeter reading the holding member I is rotated, againststop 4, and a colorimeter cell 22 is placed in the square opening of I,while securing member 9 is held to one side by hand. The securing memberis then released, bringing the colorimeter cell into correct position inthe light beam by forcing the cell against beveled edge 6 through sidepressure from edge I2. The colorimeter cell is thus positioned withlittle effort, which is a great convenience when many readings arerequired.

is indiunder test, is introduced into the colorimeter cell from apipette. The colorimeter cell being of small dimensions retains theliquid by capillary action. -";'I ;'lie;g'alvanometer now has asmallerdieflectiondetermined by the amount of light absorbed by the liquid inthe cell.

such position to aifect the light-beam intensity for a reading on themeter, said body portion being movable upwardly and away from the sampleholder for release of the latter, and said holder means being mountedfor movement parallel to said platform and across the aperture thereinto move a, positioned sample-holder away from said aperture. h

j ":2. ma colorimeter having a meter, a source of light to project alight-beam in a path and means responsive to the intensity of the light-During this filling operation, the cell is held portingand positioning asample holder in the securely in position, by pressure, between the se-vcuring member and the holding" member, 517-1 released by raisingsecuring" Upon completing a reading, the colorimeter cell can beinstantly member 9 by hand. The used cell can then be, drawn directlyout of the instrument with the other hand. However, a more convenientmethod ofdisposal is toejectthe cell into receptacle 13, This isaccomplished by raising securing member 9 with, one. handand rotati ngholding member I with the other hand in'a clockwise direction. Thecolorimeter cell,whichjmay be of non-fragile plastic material, thendrops into receptacle l3. This receptacle is held iniplatform H by afriction fit in tapered hole 29. After the receptacle is filled withcells, itis'readily removed and the cells, which are inexpensive, can bediscarded.

As previously mentioned," each time a cell is ejected in the abovemanner the zero point of the galvanometer is automatically checked byinterception of the light beam to the photocell.

.The novel features of; this invention provide a simple and convenientmeans for holding and ejecting colorimeter cells ina photoelectriccolorimeter, especially when these cells are of small size andconstructed from non-fragile, plastic materials. .r

What is claimed as new and useful and to be secured to me throughLetters Patent, is given by thev appended claims.

I claim:

1. In a colorimeter which has a light affected meter, a light-beamprojecting light and a platform with an aperture in the path of thelightbeam adapted to carry a sample holder thereon, means for acting ona' sample holder to position and releasably retain the holder in apredetermined location on the platform in alignment with the apertureandin the path of the light-beam, said means including in combinationholder means on said platform on one side of said lightbeam path,securing means having a body'portion, and means mounted above saidplatform pivotally supporting said body portion in a manner to permitpivotal movement thereof downwardly on the other side of thelight-beam'path and toward said holder means toengage and position asample holder in the light-beam path against said holder means andretain .the sample holder in beam for operating the meter, means forsup- "light-beam path, said supporting and positioning means includingin combination an apertured platform with the aperture positioned in thelight-beam path, holder means on the platform for retaining a sampleholder supported by said platform in alignment with said apertureagainst movement in one direction, securing means pivotally supportedabove the platform in a position to move downwardly and toward thelight-beam path to bear against the sample holder and urge the lattertoward the holder means, a sampleholder disposal receptacle mounted inthe platform, and means pivotally supporting the holder means formovement in a direction substantially parallel to the platform andacross the aperture therein to project-the used sample holder into thereceptacle.

3. In a colorimeter, the combination including a meter having a no-lightreading, a source of constant light projecting a light beam in a path,photo-cell means responsive to the intensity of the light in thelight-beam for operating the meter, a platform having an aperture in thelight-beam path, walled hollow means mounted between the aperture andthe photo-cell means to shield said photo-cell means from extraneouslight, said walled means permitting the passage of light therethroughfrom the aperture, to the photo-cell means and spaced from the platformsufiiciently to permit the insertion of a sample holder therebetween,movable sample-holder-positioning-and-securing means having a portion oneach of two opposite sides of the light-beam path and each portion beingmovable toward and across the light-beam path, one of said portionshaving an opaque part movable upon movement of said portionsubstantially parallel to the platform and between the platform andwalled means into a position to shut off the light-beam com pletelyprior to insertion of a sample holder in the colorimeter and to permitthe operator to observe the no-light reading of the meter, and the otherof said portions being mounted for movement away from the aperture andout of the path of said one portion to permit movement of said oneportion and the opaque part thereof into said position for interceptingthe light-beam.

DANIEL S. STEVENS.

